add extension function to validate container/annotation names

common/src/main/kotlin/nl/knaw/huc/annorepo/api/extensions.kt

@@ -0,0 +1,13 @@
+package nl.knaw.huc.annorepo.api
+
+private val restrictedChars =
+    setOf(';', ',', '/', '?', ':', '@', '&', '=', '+', '$', '.', '!', '~', '*', '\'', '(', ')', '#', '"', '%')
+
+fun String.isValidAnnotationName(): Boolean {
+    val isAscii = this.all { it.code in 0..127 }
+    val hasNoWhitespace = this.none { it.isWhitespace() }
+    val hasNoRestrictedChars = this.none { it in restrictedChars }
+    return isAscii && hasNoWhitespace && hasNoRestrictedChars
+}
+
+fun String.isValidContainerName(): Boolean = isValidAnnotationName()

common/src/test/kotlin/nl/knaw/huc/annorepo/api/ExtensionsKtTest.kt

@@ -0,0 +1,31 @@
+package nl.knaw.huc.annorepo.api
+
+import org.junit.jupiter.api.Test
+import org.assertj.core.api.Assertions.assertThat
+
+class ExtensionsTest() {
+    @Test
+    fun `these names are not valid`() {
+        val invalidNames = listOf(
+            "spaces are not allowed in annotation names",
+            "behold:a_name"
+        )
+        invalidNames.forEach {
+            assertThat(it.isValidAnnotationName()).withFailMessage { "$it should be an invalid name" }.isFalse()
+            assertThat(it.isValidContainerName()).withFailMessage { "$it should be an invalid name" }.isFalse()
+        }
+    }
+
+    @Test
+    fun `these names are valid`() {
+        val validNames = listOf(
+            "spacesarenotallowedinannotationnames",
+            "behold-a_name"
+        )
+        validNames.forEach {
+            assertThat(it.isValidAnnotationName()).withFailMessage { "$it should be a valid name" }.isTrue()
+            assertThat(it.isValidContainerName()).withFailMessage { "$it should be a valid name" }.isTrue()
+        }
+    }
+
+}